Method for detecting quality of large-diameter tubular pile at low strain

A quality inspection method and technology for large-diameter pipes, which can be used in infrastructure testing, construction, and infrastructure engineering, etc., can solve the problem of low-quality large-diameter pipe piles, achieve high measurement accuracy, low measurement costs, and eliminate high-frequency interference The effect of the wave problem

CN102877490AActive Publication Date: 2013-01-16HOHAI UNIV +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2013-01-16

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Abstract

The invention discloses a method for detecting the quality of a large-diameter tubular pile at a low strain. A plurality of acceleration sensors are arranged on the top of the tubular pile; a central angle corresponding to two adjacent acceleration sensors is 90 DEG; central angles between exciting points and all the acceleration sensors are 45 DEG or 135 DEG; acceleration responses are obtained through the measurement of the acceleration sensors, and speed responses are obtained through acceleration response integrals; an average value is obtained by superposing the speed responses obtained through the measurement at all measuring points to obtain an average speed response curve; and the integrity of a pile body is determined according to the obtained average speed response curve. By the method, a plurality of sensors are use for multipoint measurement, so that the propagation law of stress waves along the circumferential direction of a pile wall can be obtained, and the influence of a three-dimensional effect is eliminated; and due to the adoption of the average speed response curve, the problem of high-frequency interference waves can be completely solved, and the excitation of the points which form an angle of 45 DEG or 135 DEG with the acceleration sensors is better than the conventional excitation of the points which form an angle of 90 DEG with the sensors. The method for detecting the quality of the large-diameter tubular pile is easy to operate, convenient to implement, low in measurement cost, high in measurement accuracy and high in efficiency.
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Description

technical field

[0001] The invention belongs to the technical field of civil engineering, and in particular relates to a method for detecting the low-strain quality of large-diameter pipe piles. Background technique

[0002] At present, the commonly used methods for pile foundation detection include static load test method and dynamic detection method. The static load test method requires a large amount of surcharge, and it is not very convenient to implement. It can only test a small number of piles, and cannot make a comprehensive evaluation of the piles of the entire project. The dynamic detection method has been more and more widely used because of its simplicity.

[0003] There are many low-strain dynamic detection methods for pile foundations, among which the stress wave reflection method is also referred to as the reflection wave method, and its theoretical basis is the one-dimensional wave equation. The pile is regarded as a one-dimensional linear elastic member, a...

Examples

Embodiment Construction

[0027] A method for detecting the low-strain quality of large-diameter pipe piles, comprising the following technical steps:

[0028] (1) if figure 1 As shown, four acceleration sensors are evenly arranged on the top of the pipe pile. The included angle between the central angles corresponding to the adjacent acceleration sensors is 90°.

[0029] (2) Connect each acceleration sensor to a multi-channel low-strain measuring instrument.

[0030] (3) Apply the exciting force at a position where the angle between the center angle of one acceleration sensor is 45° and the angle between the center angle of the other acceleration sensor is 135°, such as figure 1 The location of the excitation point 1, the excitation point 1 generates a stress wave after being subjected to the excitation force, and the stress wave propagates symmetrically in clockwise and counterclockwise directions along the circumference of the pile wall.

[0031] (4) The stress wave first reaches the position o...